The invention relates to a supplementary appliance for producing an illuminated reticle for telescopic sights.
Illuminated reticles which are integrated in telescopic sights are known. They are, of course, linked to a specific telescopic sight, that is to say they cannot be used variably, and, together with the telescopic sight, they are relatively expensive.
Hunters have a need for a low-cost supplementary appliance for producing an illuminated reticle in low-light telescopic sights, for hunting in twilight and when the moon is full, when even a low-light telescopic sight no longer allows accurate aiming at a dark target.
A supplementary appliance which, when required, can be pushed onto the ocular area, facing the person firing the weapon, of a telescopic sight is proposed on page 38, right-hand column of Issue No. 9, December 1999 of the journal xe2x80x9cDer Jxc3xa4ger in Baden-Wxc3xcrttembergxe2x80x9d [The hunter in Baden-Wxc3xcrttemberg]. The light from a light-emitting diode is emitted as a point source in the direction of the reticle in a supporting element which leads from underneath to the center of the reticle. The crosswires in the reticle have three bars which point from the outer edge to the aiming line, that is to say to the center point or aiming point of the crosswires. If these bars are provided with a fluorescent coating, then they start to glow under the influence of the light emitted from the light-emitting diode. According to one variant, only the upper region of the aiming post glows and, like the bars which have been mentioned, this ends at a distance from the center point or aiming point of the crosswires, that is to say it also only points toward it. The light source can be switched on and off by means of a rotary switch on the appliance, and the light flux can also be regulated appropriately by the telescopic sight type.
However, this appliance still has a number of disadvantages.
Since the appliance is pushed onto the ocular area of the telescopic sight, facing the person firing the weapon, the distance to the eye is reduced in a corresponding manner, while the risk of the recoil causing injuries to the eye is increased at the same time.
It is suitable only for telescopic sights whose reticle is equipped with the fluorescent bars, which is not true of all sights.
The light from the light-emitting diode shines from the rear into the telescopic sight and illuminates the reticle completely, so that this results in insufficient contrast for the eye of the person firing the weapon.
The actual aiming point in the crosswires is not illuminated and, in fact, this must be averaged, that is to say estimated, on the basis of the fluorescent bars.
Recently, illuminated reticles have appeared for daytime, but in this case the light spot which is produced must be brighter. A stronger light source, that is to say, for example, a more powerful light-emitting diode, a large-diameter optical fiber and a lens with an appropriately adapted focal length are then required.
The object of the invention is to provide a low-cost supplementary appliance for telescopic sights for hunting in twilight and in moonlight, which does not change the distance to the eye and which produces a light point which is as sharp as possible as accurately as possible at the aiming point in the reticle, and thus also offers good contrast to the eye of the person firing the weapon. It is intended to be possible to use the appliance as required with different telescopic sights, and it must be possible to fit it to the telescopic sight, and remove it again, with a few, simple actions.
This is achieved according to the invention in that an inner ring is mounted such that it can be adjusted centrally in an annular cage which can be pushed onto the objective side of a telescopic sight, and the light from a point light source is directed onto a lens which is held on the center axis of the inner ring, with the diameter of the light beam which emerges from the light source being limited by optical means at the object-side focal point of the lens, and with the light beams which leave the lens being directed onto the aiming point in the reticle or crosswires of the telescopic sight.
Since, as an external illuminated reticle, the supplementary appliance is pushed onto the objective end of the telescopic sight, the distance to the eye does not change when it is used. The lens results in a small, sharp light spot being produced in the reticle, to be precise directly at the aiming point, whose size and intensity are equivalent to that of a conventional illuminated reticle integrated in the telescopic sight, and which thus allows the person firing the weapon to aim even in twilight or when the moon is full. Since the appliance can be fitted to the telescopic sight, and can be removed again, as required, it can also be used together with a number of different telescopic sights. It can be fitted as a supplementary device to all telescopic sights on the market, irrespective of their magnification or objective diameter.
It is preferable for the light source to be a red light-emitting diode, and the optical means which limits the diameter of the light beam which originates from the light source may be an optical fiber which projects from this light source and projects as far as the object-side focal point of the lens, or may be an aperture which is arranged at the object-side focal point of the lens. The outlet opening on the optical fiber or the aperture opening is thus imaged as a sharp, tightly limited light spot in the reticle of the telescopic sight.
The lens is preferably a convergent or collimator lens, and the light beams which originate from its focal point and arrive at it as divergent beams leave it as parallel light beams. The supplementary appliance can thus be used on telescopic sights with different distances between the outlet pupil of the appliance and the crosswires, and with different magnifications. It is thus not linked to appliances from a specific manufacturer or of a specific type.
If the lens is a convergent lens whose image-side focal point is located at the aiming point in the reticle or crosswires of the telescopic sight, the appliance is optimally suitable for use on telescopic sights with a specific focal length, and the image of the light spot is then particularly sharp and tightly limited.
Since the diameter of the divergent light beam arriving at the lens is once again limited by a further aperture arranged in front of the lens, this avoids disturbing reflections at the edge of the lens.
According to one preferred embodiment of the invention, a bush is held on the center axis of the inner ring by one or more thin struts which originate from the inner circumference of the inner ring; at its end facing away from the objective of the telescopic sight, this bush has a recess for accommodating the light source and, at its other end, has a recess for accommodating the lens, with the two recesses being connected to one another by a central passage.
Within the bush, an aperture which has an opening with a desired diameter of approximately 9 xcexcm is then arranged at the object-side focal point of the lens.
If the light beams are limited by an optical fiber which projects from the light source, then this optical fiber projects into the passage in the bush, as far as the object-side focal point of the lens. Its outlet opening is intended to have a preferred diameter of approximately 9 xcexcm. The overall length of the bush is then equal to the sum of the focal length f of the lens plus the length a of the optical fiber plus the depths b, c of the two respective recesses for accommodating the light source and the lens.
According to another embodiment of the invention, the light source is fitted to the side of the cage, and its light is carried by an optical fiber (glass fiber) to the object-side focal point of the lens which is held by struts which originate from the inner circumference of the inner ring.
The struts which originate from the inner circumference of the inner ring can end in a sleeve which is located on the center axis of the inner ring and in which the lens is held or into which the bush is pushed.
According to one embodiment, the lens or the bush is held by three struts which originate from the inner circumference of the inner ring and are held separated from one another by an angle of 90xc2x0 or 180xc2x0.
According to another embodiment, the lens or the bush is held by three struts which originate from the inner circumference of the inner ring and are held separated from one another by an angle of 120xc2x0.
According to a further advantageous embodiment, the lens or the bush is held by a single strut which originates from the inner circumference of the inner ring and ends in a sleeve on its center axis. This results in the light throughput being further improved.
The electrical supply lines for the light source are preferably carried out through one of the struts. To this end, one of the struts can be designed to be thicker and may have a longitudinal groove for accommodating the electrical supply lines for the light source.
According to one embodiment of the invention, the inner ring is mounted in the cage by means of leaf springs which are supported on the inner circumference of the cage and on the outer circumference of the inner ring, and its position can be adjusted by means of adjustment screws which pass through the wall of the cage.
According to another embodiment of the invention, the inner ring is mounted in the cage by means of helical springs which are supported at one end on a step in the inner wall of the cage and at the other end in holes which are provided for this purpose in the inner ring, and the inner ring can be tilted by means of adjusting screws which can be adjusted in the holes from the outside.
There is thus no need for any calibration firing when using the supplementary appliance according to the invention, and the light spot just needs to be made to coincide with the reticle, which can easily be done by adjusting the inner ring by means of the adjustment screws or adjusting screws.
The cage has a clamping apparatus by means of which it can be fixed firmly, such that it cannot slide, on the objective side of the telescopic sight by means of a manually operated screw, therefore without the assistance of any tools, and can be loosened again in order to remove the telescopic sight.
The light source can be switched on and off by means of a switch arranged on the side of the cage; this may be, for example, a toggle switch, a rotary switch or a push-button switch.
It is particularly advantageous if a combined switch is arranged on the side of the cage, which not only allows the light source to be switched on and off but also allows its light intensity to be varied as required.